Microinverters vs string inverters

Every solar system needs an inverter to turn the panels' DC power into AC power for your home. There are a few ways to do it, and the choice affects performance on tricky roofs, monitoring, warranty and how you add a battery.

String inverters

A string inverter is a single unit, usually on a wall near your switchboard. Panels are wired together in "strings" that feed into it.

• Pros: Generally the most cost-effective option, and well proven. Easy to access and service.
• Cons: Panels in a string are linked, so shade or a fault on one panel can pull down the output of others in that string. Monitoring is usually at the system level rather than panel by panel.
• Best for: Simple, unshaded roofs with panels facing one or two directions.

Hybrid inverters are string inverters that can also manage a battery, which can make adding storage simpler.

Microinverters

Microinverters sit behind each panel on the roof and convert power right there. Enphase is the best-known brand.

• Pros: Each panel works independently, so shade or a problem on one doesn't affect the rest. Panel-level monitoring. Easy to expand. No high-voltage DC running through your roof. Often longer manufacturer warranties.
• Cons: Usually costs more up front. Equipment is on the roof, so replacing a unit means roof access.
• Best for: Shaded roofs, multiple roof directions, smaller roof sections and systems you may expand later.

Optimisers: a middle ground

Power optimisers are fitted behind each panel like microinverters, but they don't convert to AC. Instead, they optimise each panel's output and send DC power to a central inverter. SolarEdge is the best-known example.

• Pros: Panel-level optimisation and monitoring, and strong safety features that reduce DC voltage when shut down.
• Cons: Costs more than a basic string system, and you still have a central inverter that will eventually need replacing.
• Best for: Roofs with some shade or mixed orientations, where you want panel-level insight with a central inverter.

What about batteries?

All three approaches can work with a battery. With a hybrid string inverter, the battery can be DC-coupled. With microinverters, batteries are generally AC-coupled, using a battery with its own inverter. Enphase and SolarEdge both have their own battery ecosystems, and we can also pair systems with batteries from Tesla, Sigenergy, FoxESS and Sungrow. See adding a battery to existing solar.

Which should you choose?

There's no single best option. On a simple, sunny roof, a quality string or hybrid inverter is often the best value. On a shaded or complicated roof, or if you want panel-level monitoring, Enphase microinverters or a SolarEdge optimised system can be worth the extra. We'll recommend what suits your roof and plans, and explain why.

See our solar page or get a free quote.

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